import java.io.IOException;
import java.io.InputStream;
import java.io.OutputStream;
import java.io.PrintWriter;
import java.net.ServerSocket;
import java.net.Socket;
import java.util.Scanner;
import java.util.concurrent.ExecutorService;
import java.util.concurrent.Executors;

public class TcpEchoServer {
    private ServerSocket serverSocket = null;

    public TcpEchoServer(int port) throws IOException {
        serverSocket = new ServerSocket(port);
    }

    public void start() throws IOException {
        System.out.println("启动服务器");
        ExecutorService service = Executors.newCachedThreadPool();
        while (true) {
            Socket clientSocket = serverSocket.accept();
            service.submit(() -> {
                try {
                    processConnection(clientSocket);
                } catch (IOException e) {
                    throw new RuntimeException(e);
                }
            });
        }

    }
    private void processConnection(Socket clientSocket) throws IOException {
        //打印客户端信息
        System.out.printf("[%s:%d]客户端上线\n",clientSocket.getInetAddress(),clientSocket.getPort());
        try(InputStream inputStream = clientSocket.getInputStream();
            OutputStream outputStream = clientSocket.getOutputStream()){
            Scanner scanner = new Scanner(inputStream);
            PrintWriter printWriter = new PrintWriter(outputStream);
            while(true){
                //1.读取请求并解析
                if(!scanner.hasNext()){
                    break;
                }
                String request = scanner.next();
                //2.根据请求计算响应
                String response = process(request);
                //3.把响应写回客户端
                printWriter.println(response);
                printWriter.flush();
                //4.打印日志
                System.out.printf("[%s:%d] req = %s;resp = %s\n",clientSocket.getInetAddress(),clientSocket.getPort(),request,response);
            }
        } catch (IOException e) {
            e.printStackTrace();
        }finally{
            System.out.printf("[%s:%d] 客户端下线\n",clientSocket.getInetAddress(),clientSocket.getPort());
            clientSocket.close();
        }
    }
    private String process(String request){return request;}

    public static void main(String[] args) throws IOException {
        TcpEchoServer sever = new TcpEchoServer(9090);
        sever.start();
    }
}
